We've already seen one approach to implement coroutines in the front-end using generators, in Chapter 4, Lazy Evaluation with Generators. In this section, we'll use the Co library (https://github.com/tj/co) to implement coroutines. This library also relies on generators and promises.
We'll start by walking through the general premise of Co, and then, we'll write some code that waits for asynchronous values using promises. We'll then look into the mechanics of transferring resolved values from a promise to our coroutine function, asynchronous dependencies, and creating coroutine utility functions.
At its core, the Co library uses a co() function to create a coroutine. In fact, its basic usage looks familiar to the coroutine function that we created earlier in this book. Here's what it looks like:
co(function* () {
// TODO: co-routine amazeballs.
});Another similarity between the Co library and our earlier coroutine implementation is that values are passed...